Collision strengths and transition probabilities for Co II infrared forbidden lines

TL;DR

This paper computes collision strengths, transition probabilities, and predicts line intensities for Co II infrared lines, aiding astrophysical diagnostics of supernova ejecta.

Contribution

It provides new atomic data for Co II infrared lines, including collision strengths and transition probabilities, for the first time in this context.

Findings

Calculated collision strengths and transition probabilities for Co II.

Predicted line intensities for supernova conditions.

Discussed diagnostic potential of specific infrared lines.

Abstract

We calculate collision strengths and their thermally-averaged Maxwellian values for electron excitation and de-excitation between the fifteen lowest levels of singly-ionised cobalt, Co+, which give rise to emission lines in the near- and mid-infrared. Transition probabilities are also calculated and relative line intensities predicted for conditions typical of supernova ejecta. The diagnostic potential of the 10.52, 15.46 and 14.74 micro-metre transition lines is briefly discussed.